Yea, I've been a busy fellow.

Hey Devin, some radio ahacks are better than others, I guess. Thanks for the kind comment. Good luck on your build.

Hey Devin, When this video was made radio shack was still in the DIY electronics business. They have since moved to more of a cell phone and gadget model. I will miss the old radio shack.

LOL!!!

Lol

LOOOOOOP

christofinb, thanks for the question. The booster you mentioned is akin to a tens unit. You can not use this for several reasons. It uses pulsed electrical current that is not suitable for tDCS. It may not kill you, but you would have a splitting head ache at the very least.

Jon Cammarata I thought it might not be deemed appropriate for users for brain stimulation so I thought I'd ask, thank you. I have been experimenting with it now though on the lowest setting and it seems to work quite well for a general stimulating effect and a lot of physical energy.

It is true that you could adjust resistances to achieve the proper current, but having a current regulator in the system keeps the current steady. With out it, you would notice the current drifting up or down as pads start to dry and as your body changes. For reasons I can't explain, my head tends to lose resistance during my sessions. The regulator lowers the voltage as this happens to maintain the correct current.

+CoJO' Hey bud, sorry for the late reply to this. I recommend doing a google search for tDCS montages. Also, on google scholar, search for tDCS studies. These studies will generally talk about electrode placement and then discuss the results. If the results of the study sound good to you, you can try that montage. I've tried a few montages, but I pretty much stick to the montage for working memory and alertness. The montage I use also has a small mood enhancement. I place the Anode an inch above and a half inch to the left of the center of my left eye (dorsolateral prefrontal cortex). The Cathode is placed on my right shoulder. This is pretty much the only set up I use these days. I like to do a session the day before exams or important meetings and social gatherings. Enjoy the holidays and let me know if I can be of further assistance.

Jon Cammarata That was very helpful, thank you.

You should not be telling people to review scientific articles in order to determine neuroanatomical placement if they do not have the base knowledge to determine whether or not the scientific articles' authors had sufficient knowledge to make neuroanatomical localizations accurately. I see this with fMRI all the time - compelling article.... but whoops, that part of the brain is actually something else, that does something else, and is connected to different areas. I just googled the dorsolateral PFC for shits and giggles and the intensity/immediacy of the inaccurate localizations is mind-numbing. You clearly are attempting to be systematic about this, and I respect that, but it's just not this simple. I could go on about this for a while but I will digress and privately despair about the future of society instead so I can get up during business hours tomorrow to program a functional task for a tDCS rehabilitation research study...

That is great to hear. Good luck.

@@JonCammarata One last question. Which one is the cathode and which one is the anode?

@@rowanmurphy5239 Anode is positive. Its the one attached to the circuit. The other is the cathode. It is connected to ground or negative lead on battery.

@@JonCammarata many thanks. I can't tell you how much I appreciate your video and I'm very excited to own a TDCS device!

@@JonCammarata I have mine hooked up in DARPA montage currently (anode right Temple, cathode left shoulder) I'm instead of drawing the 2 milliamps it was drawing just before, it is now drawing 0.2 milliamps. Is this normal? I can feel a slight tingle on my right temple.

Hello Dana, I graduated with a BS in Mechatronic Engineering - 4.0 GPA. I use the machine about once a week these days. I would normally plan a session during my study time. The effects seem to last about a week for me. It is most effective when you are actively trying to learn something. In other words, nothing is free. Athletes consume nutritious food, but they still have to train to get better. TDCS works the same way.

Kyle .Thompson I am so sorry for not seeing this question earlier. I bought a new phone a few months ago and stopped getting notifications for video comments. do you still need assistance?

Yeah, I tried looking up ways to wire it to the bread board but I'm still having issues getting everything in the right spot

Interesting.

Mark Allingham Every thing is going well. I don't use it as often as I have in the past. As I mentioned in the video and in other posts, it isn't very effective unless you are actively trying to learn. I am thinking of using it during video game play. There seems to be some positive results in that arena.

Sorry, forgot to mention that there have been no revisions. However, the price of tdcs units have dropped by many 100s of dollars. When I made this video they were very expensive. So, you might get a good deal on a manufactured model. But, if you are a DIY guy like me, build away. My design is as good as any on the market.

one quick question....having trouble finding a 400ohm variable resistor where I am. Do you suggest I use 2 200s in series or a 500 ohm, which I can find. Sorry, im sure this is a pretty dumb question.

Mark Allingham no such thing as a dumb question. Either of those options would work.

Hey bud, I had almost everything in my random stock. I order most of my stuff from Mouser.com or digikey.com. Ebay works, too.

Hey bud, that is just a piece of wire that i used to connect the lm317 to the resister on the bread board.

Great video by the way! Im torn between building this device or just using my dc power supply.

Well, if your PS is similar to the one I have in my lab, that would work great. Most people don't have thousands of dollars to buy a quality PS. Hence, the creation of my KZfaq video. Also, it might be smart to add 2mA Z-diode or some other reliable current regulation. Safety First

Jon Cammarata excellent point! Thank you!

No, those are quite a bit different.

Sand Nd check batteries, ensure the wet sponges are touching enough wire lead, check to see if there are any thin connections, did you use my design? Did you make any changes? Hope this helps.

Thank you so much for your reply. I'm using your design without any changes and with new batteries, everything is going great when I touch the sponges together, but when my head is the load I get 0.6 mA max, can I try to put a current regulator instead of voltage regulator or you think it's better like this? shall I decrease the resistance or any other proposition?

Sand Nd the voltage reg is configured to be a current reg. And, it appears to be working when you touch pads. Try this: Wash the area where you attach the pads to your head. Also, make sure the ramp up potentiometer (adjustable resister) can be adjusted to zero ohms. Good luck

I'm not sure I understand the question. Do you want to know the voltage across the electrodes? That depends on the resistance of you head. The current regulator will adjust voltage to achieve the 2mA current.

I did the same the ones you said, but when i check it on the sponge i saw it 18 volts

@@antoni973 18 volts is fine. You only need to worry about current. If you built your machine correctly, you will not exceed 2mA. If you check voltage at electrodes when it is not connected to your head, you will see max voltage (2x 9 volt batteries), because there is maximum resistance and almost zero current through your meter. If you connect to you leg, you should see the voltage drop as the regulator lowers voltage to maintain the target current.

The variable resister you selected should be fine. As for the other question, the vertical line is on a 0 volt leg or ground, if you will. I think I noted that the LED isn't needed and can be removed from the circuit. I hope this helps.

@@JonCammarata thanks. I'm still confused, but that is the fault of my own ignorance. But I would also like to replace both the 100k ohm variable resistor and the on switch with a 100k ohm variable resistor with built in spst switch. The on switch on your device is an spst switch, correct?

@@rowanmurphy5239 that should be fine. Get one extra incase you need more resistance to control the current. Just put them in series.

@@JonCammarata many thanks. I hope to buy the components next paycheck. I'm going to wire it exactly as you did, except with the SPST in the variable resistor as I described. That way, I can't accidentally turn it on with the resistor up at 2 amps and get that flash.

I see the same thing. One side of the switch shorts the batteries.

hi sir, im half way through my build but i designed mine differently but struggling to get the full two milliamps when adding a load to mimic the heads impedance using a simulator called proteus, wondering if u would be able help?

Taher Moshid Well, every head and montage will have a different resistance. Once you have your current regulator set for 2ma while the leads/electrode or connected to each other, you can increase ammount of input voltage until it is high enough to overcome the resistance of your head to achieve 2ma

Jon Cammarata thank you for your reply, but the problem is i got a 3 independent switches which SW1=0.5mA, SW2=1.0mA and SW3=2mA; adding only SW1 & SW3 =1.5mA, this makes it a little difficult but just wondering if you could help, in the meanwhile im kinda tweaking your schematic =)

Taher Moshid sure, no problem. I could be better help if i saw your schematic.

I do. Any lightly salted water works better than regular water.

Current limit can be adjusted but modifying resistance of the output (pin 2). I don't recommend going over 2ma. There is absolutely no evidence to support the idea that more current correlates to better results.

@@JonCammarata When you refer to "modifying resistance of the output (pin 2)", is that the LM317 regulator or the 400 Ohm variable or the 0-100 K Ohm variable resistor you're referring to? I wondered because I've seen a few devices with mA outputs extending to 3 and 4 mA and thought I should build the possibility should a correlation between more current and better results arise in the future....basically future proofing the device if possible. Also, thanks for replying so promptly. I'm a 67 year old actor trying to future proof my working life by experimenting with some 'working memory' enhancement montages to help with memorising scripts.

@@willbergman2483 pin 2 of lm317 regulator. The resistor would be around 320ohms. I did the math on my head so don't bank on it. Get 400 variable resistor put in place of the 550 ohm dial it in to what ever current you like. But, again, there will be no added benefit to increasing current. Every study that I have read on this particular subject has strong evidence that you will only increase risk, not reward.

Yes, search for TDCS machine in the Google shopping tab. Any of the 100 to 150 dollar models with 4 or more stars will work well. Go for a model with bigger pads (electrodes).

@@JonCammarata thank you so much!

chicagomike6666 The LM 317 is a voltage regulator, but can be implemented in to a circuit as a very stable current regulator, as I have done here. I don't want to spend a lot of time explaining how to do this. Just Google "lm317 as current regulator."

Great plane to learn 3d acrobatics.

Ninja Sneeze I don't have a dats sheet in front of me for the l7805 IC. If it can be utilized as a current regulator like the LM317, then yes, it would work. You'll need to check the data sheet for that chip.

In the worst case scenario, all resistors would would lose alll resistance, both regulators would stop regulating and the full 18 volts would create max current across the resistance of your head. If your head was completely saturated with salt water and the electrodes were very close to each other the current would likely just travel across your skin, causing discomfort. If the electrodes are properly placed in one of the common montages, there would be at least 6-7000 ohms of resistance. Lets assume your head has a resistance of half that of a normal head with the worst case conditions mentioned above. 18 Volts divided by 3500 ohms is 5.14 miliamps. This is still 100 times less than the current that caused lesions in lab studies. Further, there are even some studies that used 5 miliamps with no ill effects. In short, it would just be uncomfortable. Plus, there are no studies that show any benefits from going over 2 miliamps. I personally use around 1.7 miliamps. That seems to be the sweet spot for me.

ur skin will burn

That was a cool video Jon!

Hello Reza, The current is so low that you can use any size wire you want. You wont find a cable/wire that is too small.

@@JonCammarata Hi Jon, I couldn't find 400 ohm variable. Can I use 2 x 200 ohm variable in series? As to 550 ohm resistor I could only find 560 ohm online. Can I use 560 ohm and adjust the variables to arrive at 2 mA?! Thanks for your help. Sorry I'm a novice!

@@rezaadel4203 Yes, Reza, you got the right Idea. Resisters rarely match their rating perfectly anyway. If you get close, you can tweak it to perfect with the potentiometer/variable resister. Good luck.

I put a link for ammeter in description.

Thanks for your in-put John, but I am having a hard time accepting the validity of your claims. First, it is contextually inaccurate to use the word "empirically" in the manner that you did. I assume you meant to say that the evidence you acquired from your studies was imperical. If that is the case, your experiments were highly flawed. I will outline just a few faults with your claims. Fault 1: Current in a series circuit is the same throughout the circuit. This is a physical law that can not change. No matter where I place my ammeter, I will read 2mA if that is what the current regulator is set to. Fault 2: The human head has a resistance of 3000-5000 Ohms when measured through two 1.5^2inch electrode pads that have been adequately prepared with saline solution, plain water, or electrode paste. Further, the head contact area is cleansed with soapy water to remove any excess oils. I have observed these results on 5 different subjects (me, wife, mother, sister, and a friend). Fault 3: You claimed some outrageous resistances with out providing your method of measurement. This makes your claims suspect. So, there it is. I am not sure of your intent, but I have a feeling you are a skeptic. Also, I believe your attempt to debunk the circuit was strife with unsubstantiated claims. I have written and read a healthy share of lab reports, and you, my friend, do not sound like someone who is familiar with the scientific method.

None of this commentary is substantiated on either side without a commentary about the neuroanatomical localization of the electrodes, as well as a description of the SOP used to train neuroanatomical localization, and replicable standards of localization that have been mapped out to the actual brain anatomy underneath what you see on the surface. You could have a perfect setup, but if you want to induce neuroplasticity related to phonological reading skills, word finding, or decreasing the incidence of refractory temporal lobe seizures (to throw out examples) and you place your electrode on your motor cortex or by your orbitofrontal PFC, it doesn't matter what circuit you're using.

Some claim that tDCS, with the correct montage, can ease some types of pain. But, it does not work like a tense unit when placed directly on the muscle area.

@@JonCammarata are there any known working diy scematics of muscle stimulators that you know of ?

@@donsaludable3284 I am not sure. I could probably design one, but I don't have the time these days.

George Blair I am so sorry for not seeing this question earlier. I bought a new phone a few months ago and stopped getting notifications for video comments. do you still need assistance?

I need a new phone, too! I just got a new multi meter. NOT sure about contacts under the solder. Planning on a major trouble-shooting session, soon.

George Blair if you send a picture of your circuit to joncammarata@gmail.com, I will look it over for you.

Excellent! Thank you. Will do soon.

Hello David, thanks for watching my video. The placement of the electrodes is dependent upon the desired effect. Various electrode placements (more commonly known as the "montage") affect neurological processes in different ways. The montage I use is for working memory. I have a bonus effect with this montage that increases my mood, as well. Most people that want to increase memory place the cathode above the right eye and slightly off center of the eye toward the right ear. I place the cathode on my right shoulder. The anode is placed about 2 inches above the left edge of my left eye brow. I only use montages that have atleast 2 credible studies done for that particular montage that resulted in an outcome that I am interested in. I highly recommend, to anyone interested in doing this, reading and researching until they are confident that they know what they are doing. I hope this helped, David. If you want anymore info, just ask. I am more than happy to help.

Jon Cammarata Thanks for responding Jon. I have done substantial literature research myself on tDCS, but I am alarmed by the amount of do-it-yourselfer's who clearly have no idea what they are doing regarding circuit construction, loading effects or electrode placement. Although most of the studies have shown positive benefits of tDCS compared to sham and control groups, my main hesitation is from the lack of research on the long term effects. What are your thoughts on this? Have you noticed any negative side effects?

David Vutetakis Hello again, David. The long term effects are, as you say, not really known. Only time will tell. As of yet, I have not noticed any negative effects. I do notice a decrease in the enhanced focus and memory after about 20 days with no tDCS. However, the knowledge and memories I acquired, while I was using the device regularly, have remained. In short, I can't speak to the long term negatives. I am a full time engineering student so my brain is constantly being challenged. I am curious if that has made the effects more evident to me when compared to other tdcs users.

Jon Cammarata From some of the research I have done, it is most effective if you simultaneously perform an activity which uses the area of the brain being stimulated. I too am an engineering student in the second semester of my masters degree, so it seems like we have similar reasons for our interest haha. It is the unknown long term effects that has prevented me from trying it though.

David Vutetakis It is true that no study focussing on the long term has been published. However, there is a common consensus amongst researchers that it is safe at the current levels on intensity.

Hi Mark, I don't have links. I could put some but these types of components chang scew so often that I would be on constant update mode. Try online sources like digikey, mouse, or automation direct. Also, this video was made 3 years ago - back when tDCS devices were over 500 dollars. You can actually find some well built devices for less than 100 dollars. Do a Google search and check Amazon, as well. I hope this helps.

Thank you for the very quick response, and thank you for the suggestions!

I can't seem to find a 400 ohm variable resistor cheap online. Where did you get yours? Thanks.

Also, is a 540 ohm resistor in place of the 550 ohm resistor and a 500 ohm variable resistor instead of a 400 ohm variable resistor ok?

@@markfogelson4252 yes, that will work. You can also search for rheostat. Or use a 200 ohm register in series with a 200ohm variable resistor. That would give you 200-400ohm variance.

This is direct current. The frequency is zero.

@@rapolass2585 Yes ! I actually got to figure that out later on. Thanks for your reply tho ! I appreciate it :)

gaurav kesharwani it is impossible for 18volts DC to be fatal (in this applicatiobl). Further, the electrodes would become far to uncomfortable to continue before it became dangerous.

Manchester England United kingdom.Dear Jon, Hi good morning, Many thanks for your video ( how to make a tdcs ) I've suffered from depression etc. ( etc. being that which comes with depression ( i.e. ) brain fog, none clarity. ) for the most part of my life. Now aged nearly 70 y o age, and I now see, tdcs as a last hope. Is al the electrical components necessary, why not just use a larger or smaller volt battery and from there to the fore head. Many thanks again for your time, and the video. GOD BLESS THE FREE WORLD AND THOSE THAT KEEP IT FREE. Yours Most Most Sincerely Peter.

@@JonCammarata If one were to drop the circuit into a big box of HUGE capacitors... perhaps... just maybe!

Another name is trimmer resister. This 1k ohm trimmer will work just fine. www.amazon.com/Trimmer-Resistors-Through-1Kohms-0-5watt/dp/B00M1XAFPY/ref=sr_1_1?ie=UTF8&qid=1469239368&sr=8-1&keywords=1kohm+trimmer+resistor

+Jon Cammarata just set it to the resistance I specified in the video. let me know if you need any other assistance.

I went back to radioshack an hour ago and just got back, I figured the 1k ohm variable resistor at a low setting will work so I went back for it, i also picked up a 330 220 resistors to get a 550 ohm. I had a 560 but was worried it wont do. I also found cheaper ammeters on ebay, which one do you recommend? I'll use my multimeter for now. thanks for the reply, ill come back here when I have more questions thanks! (I hope this will help with my ADHD)

take some stuff apart, you will learn some interesting things and end up with a pile of parts :)

+curtis133 So true! Excellent comment curtis.

neuemage No, but if i am not careful I start walking in circles.

@@JonCammarata HAHA! Funny, but serious. :)

How true, my friend. This is one of my oldest videos. Those stores are all extinct. You can try adafruit, mouser, or digikey and the like to make online purchases. Good luck.

@@JonCammarata Is it a big deal if I use a 560 Ohm resistor instead a 550 Ohm one? The internet is full of 560 ohm resistors but I cant find no 550 ones

@@thomaskreisel5764 Nope, that should be just fine.

@@JonCammarata I would like to know why you are using 2 batteries instead of 1. Wouldnt one 9V battery be enough?

@thomaskreisel5764 There are a few reasons. The current regulator works better with the higher voltage. The internal resistance of 9 volt batteries is high. So, the extra current availability tends to help.

+Teejay Chiwetalu Hello Teejay, I've been using this for over a year now. The effects are subtle with one exception. I always feel very focused the day after a session. The only evidence I can provide, is this. I am a 4.0 GPA Mechatronic engineering student. Prior to tDCS, I averaged 95-96% in all of my classes. After tDCS, I average around 98.5% for all of my classes. I always take the new IQ practice tests when they are available - wonderlic, Mensa practice, etc. I don't mess with those cheesy social media tests. I only use the official practice tests from reputable sources. In the past, I scored in the lower 130's IQ range. I've taken two tests with in the past 6 months. One indicated an IQ of 140, the other 138. So, as you can see, the changes aren't drastic by any means. None the less, the numbers have changed for the better. Also, it's important to remain transparent when talking about tDCS. So, I will mention this. If I do more than 2 sessions a week, I get a headache, not a severe headache, but more of a dull head ache. I liken the headache to that which you might get after studying to long and hard.

Good stuff!! That's one of the minor side effects noted by researchers.

I don't quite understand your question.

The voltage across the electrodes is the remaining voltage after the voltage drop across the other components in the circuit. For instance, if there was a simple circuit with 2 resisters of equal value and a 2 volt battery, the voltage measured from between the two resisters to ground would be one half of the supply voltage. In this example the voltage would read one volt between the equal resisters.

Also, if you want, just ask the question in your own language and I will translate it on my end.

​@@JonCammarata I think he wanted to know why you don't use a 3v cell. Perhaps 2 AA batteries instead. Perhaps he was confusing voltage with milliamperage.

@@Reach3DPrinters 3 volts doesn't have quite enough potential to achieve 2mA. The average head presents a few thousand ohms of resistance. Using Ohms law: 3 volts divided by 2mA =1500 ohms. 1.5 kilo-Ohms is far lower than the average head. So, that's why I use 9Volts. It's enough to achieve 2mA with-out being dangerous. In other words, you could hook the battery directly to your head but you are unlikely to damage yourself unless you had amazing pain tolerance and held it there for quite a long time.

Hard to say without know the brand. Check digikey.com, newark.com or mouser.com. If you have them on hand, you can measure with an ohm meter.

@@JonCammarata thanks

really?

Hello milky chicken, I prefer to answer question here in the comment section. That way all can share the information. Thanks.

Philip Doyle - hey bud. It sounds like the polarity of your ammeter is reversed. Try swapping the connections arround. Then, using a voltmeter, touch the your leads to the electrodes. If the voltage is negative, swap the leads. The electrode that is touching the red lead from your volt meter is the anode. I hope this helps

Thank you Jon for such a quick response. You were absolutely right about the polarity being wrong but it turns out that there may also be something wrong with the analogue ammeter I bought because now the needle does go beyond the 0 point but when the ramp up potentiometer is turned all the way (to maximize current) it only goes up until about 0.3 milliamps. When I used my multimeter instead the current did climb all the way to 1.92 miliamps. All to say thank you for your help and for the video I'm looking forward to using this machine the research does look promising.

Francesco Medina Thank you very much for the great compliment.

Jon Cammarata I did everything acording to your video and i'd like to ask you these little questions: 1) since i never tried a tdcs device i don't know if the current is perceptible. Setting at 2mA I don't feel any tingling. It is normal? 2) im notice that cathode (black color) goes to the ground and anode (red color) is connected to the output of the 0-100kohm variable resistor. Is it correct?

That is correct, Francesco. However, you should put the ammeter between the positive electrode and the ramp up (variable) resistor to ensure that you are producing 2mA. I always feel a tingle. It is possible that you may not feel any tingle if the electrodes are very large.

Also, if you are sure, send me a clear close-up picture of your circuit and I can look it over for you.